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Quick Facts

Yellow Fever


The Manual's Editorial Staff

Last full review/revision Mar 2020
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What is yellow fever?

Yellow fever is a viral infection spread by mosquitoes.

  • You get yellow fever from being bitten by an infected mosquito

  • Mosquitoes in tropical areas of central Africa, Central America, and South America carry yellow fever

  • It causes headache, dizziness, muscle aches, and fever

  • Sometimes, your skin and eyes turn yellow (jaundice) because the disease affects your liver

  • Yellow fever can be deadly if it severely affects your internal organs

  • The best ways to prevent yellow fever are by getting the vaccine (shot) and avoiding mosquito bites

What causes yellow fever?

Yellow fever is caused by a virus. The virus is carried by certain animals that live in tropical areas of South America and Africa. When mosquitoes bite an infected animal or person, they pick up the virus and give it to the next person they bite.

What are the symptoms of yellow fever?

Some people don’t have any symptoms.

Early symptoms include:

  • Sudden headache, fever, chills, and muscle aches

  • Feeling weak and dizzy

  • Feeling sick to your stomach and throwing up

These symptoms go away after a few days. Most people have no more symptoms and recover from yellow fever. Other people get more serious symptoms.

In severe cases, the virus can affect many of your organs, including your liver, kidneys, and heart. Later symptoms of yellow fever include:

  • High fever

  • Throwing up blood

  • Yellow skin and eyes (jaundice)

  • Bleeding from your nose, mouth, or intestines

  • Dangerously low blood pressure

  • Seizures and coma (in severe illness)

How can doctors tell if I have yellow fever?

Doctors suspect yellow fever if you have symptoms and have been in an area where there are cases of yellow fever. To know for sure, they’ll do blood tests.

How do doctors treat yellow fever?

There's no cure for yellow fever. Doctors will treat your symptoms and give you:

  • Fluids by vein to keep your blood pressure up

  • Medicines to treat or stop bleeding, such as vitamin K, which helps your blood to clot

  • Sometimes, put you on a machine to take over for your kidneys (dialysis) and remove waste from your body

  • Keep you in a room that is screened and sprayed with bug spray to prevent mosquitoes from spreading the virus to other people

How can I prevent yellow fever?

Avoid mosquito bites

If you live in or visit areas with yellow fever, take steps to avoid mosquito bites:

  • Put bug spray with DEET on your skin

  • Spray or soak your clothes with an insect repellent containing permethrin

  • Use mosquito nets

  • Wear long-sleeved shirts and long pants

  • Avoid going outside if you don't have to

Get the vaccine if you're going to an area with yellow fever

A vaccine is available to prevent yellow fever and should be taken 3 to 4 weeks before you go.

  • In the United States, the yellow fever vaccine is given at travel medicine clinics, located throughout the country

  • Most people can get the vaccine, with the exception of babies younger than 6 months old, pregnant women, or people with weak immune systems—talk to your doctor about getting the vaccine

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